Method for ensuring data coherency for redundat storage by transferring copies of access requests from on-line storage to back-up storage
AssigneeHitachi, Ltd.
InventorsYuzuru Maya, Soichi Isono, Akira Ohtsuji
Life of this patent
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Abstract
A command is issued from a processing unit to an on-line storage unit and transferred from the on-line storage unit to a back-up storage unit. The received commands are processed in the respective storage units. An overhead of the on-line storage unit is reduced in a hot stand-by system. Storage contents of the on-line storage unit and the back-up storage unit are made coincident in a structure having a plurality of processing units, where the on-line storage unit and the back-up storage unit are connected through a channel device.
Claims6
In a computer system comprising two storage units having processors, one being an on-line storage unit and the other being a back-up storage unit, and a processing unit for accessing said storage units by issuing commands, a method for making storage contents of two storage units coincident comprising the steps of:
- issuing a command from said processing unit to said on-line storage unit;
- transferring the command received by said on-line storage unit to said back-up storage unit;
- and
- executing respective processes for the received command in said on-line and back-up storage units.
A computer system comprising:
- a first storage unit having a processor working as an on-line storage unit;
- a second storage unit having another processor working as a back-up storage unit;
- and
- a processing unit for accessing said first storage unit by issuing a command thereto;
- wherein
- said first storage unit sends said command to said second storage unit and execute a process in accordance with said issued command, and said second storage unit executes a process in accordance with said sent command.
Dependencies are inferred from the claim text.